Johnson & Johnson heiress Casey Johnson struggled to control her almost lifelong battle against diabetes for more than 20 years — and the disease ultimately killed her. Johnson died of “diabetic ketoacidosis” — described as “an absolute shortage of insulin” — the Los Angeles Coroner announced on Thursday.

The cause of death was “natural.”

The troubled socialite, who was allegedly engaged to marry wacked-out reality star Tila Tequila, was found dead in her Los Angeles home on Jan. 4. She was 30. Johnson left behind her 3-year-old adopted daughter Ava, who is currently being cared for by Johnson’s mother Sale Johnson.

Earlier today, the L.A. Coroner’s Office also announced the cause of death of actress Brittany Murphy. Murphy, 32, died of a combination of multiple drug intoxication, pneumonia, and iron deficiency anemia.